Transmitting and receiving system



TRANSMITTING AND RECEIVING SYSTEM Filed March 17 1926 Inventor; Garey PISA/99mg,

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Patented July 1, 1930 UNITED STATES PATENT. OFFICE CAREY P. SWEENY, OF ROCKY POINT, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK TRANSMITTING AND RECEIVING SYSTEM Application filed March 17, 1926. ,Serial No. 95,388.

My invention relates to systems for transmitting and receiving electrical impulses by radiotelegraphy or radiotelephony, and has for its principal object the provision of an improved transmitting and receiving 'apparatus which is operated efiiciently and smoothly by energy supplied from an alternating current source.

In the transmission and reception of electric impulses by radiotelephony or radiotelegraphy, it is customary to utilize a thermionic device provided with a grid for controlling the transmission of current between its cathode and anode. Such a device operates most efliciently if its resistance is suddenly decreased at the beginning of the period during which it transmits current and is suddenly increased at the end of this period. In accordance with my invention, this result is produced through means comprising avapor electric rectifier interposed between the'thermionic device and an alternating current source from which this device is supplied with current. My invention will better be understood from the following description when considered in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

-The drawing is a diagrammatic showing of a transmitting apparatus wherein my invention has been embodied.

This apparatus comprises a circuit to be energized, shown as an antenna 1, and an alternating supply circuit 2, which are interconnected through a polyphase transformer 3, mercury rectifiers 4 and 5, a thermionic device 6, and a transformer 7 which comprises a primary circuit 8 and a secon- The transformer 3 is provided with a primary circuit 10 and with secondary circuits 11 and 12, which have the r neutrals interconnected through aninterphase transformer 13 and have their terminals connected respectively to the anodes 14, 15 and 16 of rectifier 4 and the anodes 17, 18 and 19 of rectifier 5. The rectifier 4 is provided with exciting electrodes 20 and 21, a mercury cathode 22, and a starting electrode 23 which is connected to the exciting electrode 21 through a resistor 24. The rectifier 5 is likewise provided with exciting electrodes 25 and 26, a mercury cathode 27 and a starting electrode 28 which is connected with the exciting electrode 26 through a resistor 29. The thermionic device 6 comprises a cath ode-30, a grid 31 connected to the cathode through a grid 'leak as shown, and an anode 3:2. The cathode 30 is heated by current supplied from a suitable source through a transformer 33, and the excitation of the rectifiers 4 and 5 is maintained by current supplied from this source through transformer 33 and smoothing reactors 34 and 35 connected between the mercury cathodes and the exciting electrodes of devices 4 and 5 in a manner well understood by those skilled in the art.

It will be observed that the mercury cathodes of the rectifiers 4 and 5 are connected to the anode 32 through a filter shown as comprising a series inductance 36 and shunt capacities 37 and 38; that the winding of the interphase transformer 13 is connected to the cathode 30 through circuit control means shown as a key 39; that the cathode 30 is connected to the transformer winding 8 at a point intermediate its ends; and that the anode 32 and grid 31 are connected to the ends of the winding 8 respectively through blocking condensers 40 and 41 which are provided for keeping the direct current out of the winding 8.

With these connections, the devices 4, 5 and 6 are maintained in a condition to transmit current by means of heating and eXciting current supplied through the transformer 33 but no current is transmitted between the alternating circuit 2 and the antenna 1 while the key 39 is in its illustrated open position. Upon closure of the key 39, however, the direct current voltage of the rectifiers 4 and 5 is applied to the anode 32 and cathode 30 of the thermionic device 6, the resistance of this device is suddenly decreased to a comparatively low value due to the fact that as the rectified voltage which issubstantially constant in value, is applied to the anode 32, a voltage is applied to the anode end of the winding 8 through con ing an anode, a cathode and a control grid, denser 40 and a corresponding voltage of of an anode supply means for said device inlike' polarity is induced in the lower section cluding a polyphase transformer having a of the winding and is applied to the grid secondary circuit provided with a plurality 31 through the condenser 41 since these secof terminals including a neutral terminal, a 70 tions are connected in opposing relation with mercury arc rectifier provided with a cathode respect to each other. Thus with a positive and a plurality of anodes each connected potential applied to the anode, a positive with a different terminal of said secondary v instantaneous potential is applied to the circuit, an anode supply circuit for said grid, thereby decreasing the resistance of thermionic device arranged to be connected 7 the device 6. Current is then efliciently between the cathode of said rectifier and transmitted through the device 6 and the with the neutral terminal of the transformer primary circuit of the transformer 7. Likesecondary, means for closing and opening wise, w an the key 39 is opened, the potensaid connection to energize said circuit, and

tial of the grid 31 is suddenly reversed, the circuit means including an inductance con- 80 resistanceof the device 6 is suddenly innected with said anode, cathode and grid creased to a comparatively high value and of the thermionic device operable to vary loss of power in the device 6 due to the transthe potential of the grid in accordance with mission of current while its resistance is the energization of said anode supply cirhi h is avoided. cult. 5

heembodiment of the invention illus- In witness whereof, I have hereunto set tratcd and described herein has been selected my hand this 13th day of March, 1926. for the purpose of clearly setting forth the a CAREY P, SWEENY. v principles involved. It will be apparent, however, that the invention is susceptible of being modified tomeet the different conditions encountered in its use and I therefore aim to cover by the appended claims all modifications within the true spirit and scope 0 of my invention. I What I claim as new and desire to secure by Letters Patent of the United States is: 1. The combination of a polyphase mercury are rectifier having a plurality of i 35 anodes and a cathode, a thermionic device having a cathode, an anode and a grid for controlling the transmission of current between its cathode and anode, means for com-- pleting a circuit between the anodes and 40 cathodes of said rectifier and said thermionic device, a transmitter circuit including the anode andcathode of said thermionic device, an antenna coupled with said circuit where by said antenna is energized when said last 45 named circuit is completed, and means opno erable tovary the potential of said grid in accordance with the energization of said antenna.

2. The combination with a radio trans- 50 mitter embodying a thermionic device, of an anode supply means for said device including a polyphase transformer having a secondary circuit provided with a plurality of terminals including a neutral terminal, a 55 mercury arc rectifier provided with a cathode and a plurality of anodes each con nccted with a different terminal of said secondary circuit, an anode supply circuit for said thermionic device arranged to be con 60 nected between the cathode of said rectifier i and the neutral terminal of the transformer secondary, and means for closing and open ing said connection to energize said circuit. 3. The comb'nation with a radio trans mitter embodying a thermionic device 

